Recently, Bluetooth communication between a vehicle terminal and a user terminal, such as a smart phone, has been widely utilized, such as playing a playlist of songs stored on the smart phone through the vehicle's audio stereo system, or providing a voice call through a vehicle speaker. As long as security is ensured in Bluetooth communication, the vehicle terminal will be able to utilize additional information via the smart phone, such as personal information for providing customized services to users in their vehicles, which otherwise would not be available. Therefore, it is necessary to ensure security in the Bluetooth communication between the vehicle terminal and the smart phone.